Update: I was unfortunately not aware of Shamus Young's severe criticism of Fallout 3 available here to link in the original piece and I regret that. It dovetails rather nicely with what I've written and it's much better executed than my piece. I strongly recommend anyone...

Hints

See the Titanic:
To see the Titanic you must First go to the Canada Autumn stage and then go
to the three dirt roads and finally go to the far left. Look out to the sea
you will see the Titanic.

Clean Pause:
Press the start button to pause the game, then press and hold down the Y button
and press the X button.

Infinite Laps:
When selecting tracks go to the option screen. then turn weather to sun, time
to day, mirror on, nitro on, checkpoint on and the other two off. You will get
infinite busters as well. If this doesn't work, enter it after the code for
all cars and tracks. So far I know it's for arcade mode only.

Play Class S in Championship Mode:
In championship mode, if you beat finish Class A (beat Driver X at least 3 times)
Driver X will ask you to race with him. You can use his car if you win the match,
and you will pass to Class S. In this class, all enemies are the same as Class
A except Driver X.